This patch introduces a queue to store ids of transactions that failed
to send a rollback fragment in streaming_rollback(). This is to avoid
potentially missed rollback fragments when a cluster splits and then
later reforms. Rollback fragments would be missing if a node rolled
back a transaction locally (either BFed or voluntary rollback) while
non-primary, and the attempt to send rollback fragment failed in
transaction::streaming_rollback().
Transaction that fail to send rollback fragment can proceed to
rollback locally. However we must ensure that rollback fragments for
those transactions are eventually delivered by the cluster. This must
be done before a potentially conflicting writeset causes BF-BF
conflicts in the rest of the cluster.
* Added unit tests for transaction::xa_detach() and
transaction::xa_replay()
* Added unit tests for wsrep::xid
* Fixed minor issues pointed out by reviewer
- High priority interface method to apply NBO begin, separate from
apply_toi() in order to avoid implementation to force interpreting
ws_meta flags.
- Method to put client_state into NBO mode when applying NBO begin.
The client_state will process in m_local mode.
- Unit tests for applying NBO
- populate and pass real error description buffer to provider in case
of applying error
- return 0 from server_state::on_apply() if error voting confirmed
consistency
- remove fragments and rollback after fragment applying failure
- always release streaming applier on commit or rollback
* Enable codepath to BF abort high priority SR applier
* Pass ws_handle, ws_meta to high priority service rollback
call to allow total ordering of rollback process
The write set handle and meta data are needed for SR transactions
where the commit context is not known when the transaction starts.
The passed handle and meta data can be set through client_state
prepare_for_ordering() call before performing commit.
